Database / SQL

Question 1

Database

Answer 1

organized info so it can be accessed, managed and updated.

od amu

Question 2

Relational DB

Answer 2

Type of DB where tables are related / linked by common data.

Question 3

Tables

Answer 3

contain rows and cols. rows aka records. cols aka attributes.

Question 4

Relational DB management system

Answer 4

a program that allows you to manage a relational database .

e.g. such as create and update info.

Question 5

SQL

Answer 5

Structured Query Language

program language that allows user to communicate w/DBs. It allows to request data, or perform actions on data.

Question 6

Why SQL

Answer 6

DTE
data + table + ebed
data = (MADD) allows users to access, describe, define, manipulate data
table = C(v)SD
C = tv
S= tv
allows users to create tables and views. drop tables. set permissions on tables and view and create stored procedures and fxs

Question 7

Draw SQL Architecture

Answer 7

SQL query
query language processor < parser + optimization
DBMS engine < flies manager + transaction manager
Physical DB

Question 8

What is a primary key

conditions:

Answer 8

a field uniquely identifies each record in a table.

• only 1 unique primary key for table
• each must contain unique values
• no null values

Question 9

What is foreign key

Answer 9

links 2 tables together. aka referencing key.
the relationship (link) is the primary key matching the foreign key.
is a column

Question 10

creating primary key

steps to create

Answer 10

-usually created while creating the table, but can be created after creation of table.

1. create table
2. create primary table

1.
a. write command “create table”
b. name table “x”
c.

Question 11

sql statements

Answer 11

= used to perform tasks such as update and retrieve data.

d^3 (dmcc) L^4

table cad
data siud
permissions gr
db transactions src

Question 12

SELECT Query

what are ways to select data

Answer 12

=allows you to select and get data from table.
results are returned in tables called result-sets.

-fetch ALL fields
SELECT * FROM table_name
SELECT column1, column2, FROM table_name;
eg: SELECT ID, NAME FROM CUSTOMERS

Question 13

INSERT Query

how

Answer 13

= adds new rows of data to table

INSERT INTO table_name (column1, column2)
VALUES

Question 14

What is SQL WHERE

Answer 14

used to specify a condition when fetching data.

WHERE [condition]

Question 15

What are JOINS

Different types?

Answer 15

is a condition allows combine records from 2 or more tables.

Types = 4
Full, inner, left and rt